------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 0 PID: 20605 at lib/refcount.c:25 refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 0 PID: 20605 Comm: syz-executor.1 Not tainted 5.12.0-syzkaller-08136-gd72cd4ad4174 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO BTYPE=--)
pc : refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
lr : refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
sp : ffff80001b717b30
x29: ffff80001b717b30 x28: ffff80001b717cf4 
x27: ffff0000315d8000 x26: 1ffff000036e2f9e 
x25: 1fffe000023df693 x24: ffff80001b717d00 
x23: 1ffff000036e2fa0 x22: 0000000000000004 
x21: ffff80001717cd00 x20: ffff0000315d9108 
x19: 0000000000000002 x18: ffff00006ab19b48 
x17: 0000000000000000 x16: 0000000000000000 
x15: ffff00006ab19b7c x14: 1ffff000036e2ea4 
x13: 0000000000000001 x12: ffff60000d563384 
x11: 1fffe0000d563383 x10: ffff60000d563383 
x9 : dfff800000000000 x8 : ffff00006ab19c1b 
x7 : 0000000000000001 x6 : 00009ffff2a9cc7d 
x5 : ffff00006ab19c18 x4 : 1fffe000027859d9 
x3 : dfff800000000000 x2 : 0000000000000000 
x1 : 0000000000000000 x0 : ffff000013c2cec0 
Call trace:
 refcount_warn_saturate+0x108/0x1a0 lib/refcount.c:25
 __refcount_add include/linux/refcount.h:199 [inline]
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 kref_get include/linux/kref.h:45 [inline]
 j1939_netdev_start+0x5fc/0x900 net/can/j1939/main.c:250
 j1939_sk_bind+0x2c8/0xd30 net/can/j1939/socket.c:479
 __sys_bind+0x16c/0x1d0 net/socket.c:1637
 __do_sys_bind net/socket.c:1648 [inline]
 __se_sys_bind net/socket.c:1646 [inline]
 __arm64_sys_bind+0x6c/0xa0 net/socket.c:1646
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x6c/0x260 arch/arm64/kernel/syscall.c:52
 el0_svc_common.constprop.0+0xc4/0x1e4 arch/arm64/kernel/syscall.c:145
 do_el0_svc_compat+0x40/0x7c arch/arm64/kernel/syscall.c:190
 el0_svc_compat+0x24/0x3c arch/arm64/kernel/entry-common.c:500
 el0_sync_compat_handler+0x90/0x140 arch/arm64/kernel/entry-common.c:509
 el0_sync_compat+0x190/0x1c0 arch/arm64/kernel/entry.S:752
irq event stamp: 1672
hardirqs last  enabled at (1671): [<ffff800014431bcc>] __raw_spin_unlock_irq include/linux/spinlock_api_smp.h:168 [inline]
hardirqs last  enabled at (1671): [<ffff800014431bcc>] _raw_spin_unlock_irq+0x78/0x15c kernel/locking/spinlock.c:199
hardirqs last disabled at (1672): [<ffff800014410394>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:241
softirqs last  enabled at (1642): [<ffff80001365e210>] lock_sock_nested+0xf0/0x1d0 net/core/sock.c:3065
softirqs last disabled at (1640): [<ffff80001365e170>] spin_lock_bh include/linux/spinlock.h:359 [inline]
softirqs last disabled at (1640): [<ffff80001365e170>] lock_sock_nested+0x50/0x1d0 net/core/sock.c:3057
---[ end trace 54714fab132984b4 ]---